This
species was one of the first piranha I ever owned in 1964, where it was
purchased at a pet store as a juvenile. It was also the one and only piranha to
bite me by accident in 40 years of keeping these species. These first specimens
of piranha were also used in my own home test on cold tolerance (VIEW). Subsequently, many
more were added to my growing collection over the years. During 1980, I
had 2 successful spawning of the species. Pygocentrus nattereri is a
complex species with many variations of spotting, body shape and coloration.
Much of the morphology is dependent on water chemistry and food. Another problem
that comes into the mix is that P. nattereri is readily bred in home
aquariums. So the coloration or body shapes appear dissimilar to wild caughtVIEWP. nattereri.
Because of these changes that occur, hobbyists are sometimes confused by the
differences seen with wild caught vs. tank raised. That is understandable. Wild
caught colors are more brilliant in their native waters, but once put into the
environment of the home aquarium, the stress and lack of natural foods takes a
toll on the fishes appearance. And that is where the confusion begins when a
hobbyist sees a red-belly piranha that may have a different head shape or dull
colors. Much argument over size of jaw is similar to arguments once brought
forth by old science, but now we know that such traits are individualistic and
should only be considered as a small fraction of how to identify a species.

Please
take you time and read through this entire web page including its links. It will
help you get a better understanding how complex these species are.

Recorded
examples range from 30-35 cm total length. Aquarium specimens are usually
smaller. Being the most common piranha found for sale in U.S. pet industry,
these fish has provoked fear in conservationists and the media (see genus PygocentrusVIEW). The fish
are found in a variety of belly colors ranging from yellow-orange-red. Body
colors are also as variable being; silver-gold-black. Some are so intensely
gold-speckled that they are also commonly called "gold-dust piranha".
The head shape of these piranhas also appear to be variable, some being very
blunt-headed and having little to no concavity above the profile of the eyes.
This has been attributed to the type of diet the fish is restricted to. This
species is relatively small, with a 3- pound 7-ounce specimen holding the world
angling record, River Cuiaba, Mato Grosso, Brazil. (Source: Field and Stream
2002). Some imported Pygocentrus type piranhas have been reported to
lack the presence of the adipose fin or the adipose fin is reduced in size.
Researchers are reminded that without the naturalness (synapomorphy) of the
adipose fin the fish would not be a member of the subfamily Serrasalminae.
Piranhas do bite each other and the loss of an adipose fin can be attributed to
that. As for reduction in size, that depends on environmental factors and diet,
after all the adipose fin is fatty tissue and not unreasonable to assume that an
emaciated fish lives on its fat storage when faced with periods of drought. The
area above the eyes (dorsum) is also seen in some wild caught specimens and the
occasional pet trade piranha to appear very emaciated (skinny and drawn). This
piranha must be encouraged to eat fish and other matter, since the dorsum area
is a fat and muscle storage area. Hobbyists also look at body length to assume
this character prescribes a different feature, Fink in his revision did a body
comparison of all P. nattereri within its range and found nothing
to suggest that elongation of the body is a specific feature in one locality.
Indeed elongation is more an individualistic trait within populations of P.
nattereri throughout its range. Some species like Pygopristis denticulata
require the feeding of seeds VIEW (Magallanes, 1993) in order for
the fish to replace this fatty tissue.

LONGEVITY
IN CAPTIVITY

In nature, piranhas are eaten by other animals and of course
cannibalized by their own relatives, so many do not live long. In the aquarium,
that is another matter. Reported ages in captivity run from a few days and in a
few are cases over 20 years. However, 10 years seems to be the norm via aquarist
care. For those that enjoy keeping piranhas as pets, they can live for
quite some time. Meet Petey the Piranha. *This "Terror of the Esopus"
was captured in 1964 after years of terrorizing tubers. He lived happily in
captivity until he died of old age in 1982. Watch your fingers!* Petey is a gag.

DEATHS
ATTRIBUTED TO PIRANHAS

Scavenging
on human corpses as a source for stories about man-eating piranhas Ivan Sazima
and Sérgio de Andrade and Guimarães. Synopsis Piranhas have a reputation for
man-eating, notwithstanding the absence of authenticated records of persons
attacked and killed by these fishes. Three cases of piranhas scavenging on human
corpses were recorded in Mato Grosso, western Brazil. One corpse, found four
days after drowning, was almost reduced to a skeleton. Another corpse was
recovered in a few hours, also after drowning, without the soft parts of the
head. The third corpse, recovered 20 hours after the victim fell into the water
due to a myocardial infarction, had flesh only on the trunk. Pygocentrus
nattereri and, to a minor extent, Serrasalmus spilopleura were
probably the necrophagous piranhas. Some of the human deaths attributed to
piranhas most probably are cases of scavenging on drowned or otherwise already
dead persons, by these opportunistic schooling carnivores.

ALBINISMS
and BREEDING

A hobbyist
several years ago purchased a purported albino piranha. This fish while
interesting does not appear to have the recessive gene that creates albinism in
species. Nor does it exhibit the pink eye associated with such albinism. It
could be called a "golden piranha" based on its color alone. The fish
is likely a geographic variation, however, sometimes parasites can cause similar
problems, but the fish looks in good health. (SEE PHOTOS BELOW)

The fish
has plenty of red pigments mixed in with the yellow. This could later become
redder if the fish becomes ready to reproduce. It was raised in dim light which
would help explain part of the reason it lacks the intense coloration of the
body. The fish was originally purchased from a piranha breeder in Ohio who has
been producing this color (belly) variety for a number of years. The juvenile
fish was then sold to another person (who kept the fish in dim light) which
eventually made its way to the Pira-News2000reader.
The original fish breeder and I are old friends and I was fortunate to receive a
few of these fish as gifts for OPEFE. Fink was also provided some samples and he
was surprised the fish maintained its bright yellow belly color after being bred
for so many years in the aquarium. Albino piranhas may or may not exist
in nature. In my 50 years of examining piranha I have never seen one. Nor has
Dr. William L. Fink, though he did intimate the possibility of its existence in
nature. As discussed below, such critters are normally eaten by the clan as
inferior. Piranhas raised in little to no light suffer from nutritional losses
the sun (or artificial light) provides. The chromatophores (stellate cells)
which produce color require certain vitamins which natural sunlight provides.
This pigment and refractive granules are important and if they do not get light
then certain things can happen to the pituitary gland which controls the hormone
(called intermedin).

COLOR
OF LIFE BY POPULATION: Read about P. nattereri and its geographical
variations (ie; Super Reds, Ternetzi, etc): VIEW

Pygocentrus
nattereri, from the Mato Grosso region of Brazil, the type collected from
both the Amazon and Rio Paraguay systems, described by Kner (1860) as Pygocentrus.
Considered the earliest available name for the undiagnosed species composed of
Pygocentrus populations residing in those areas (William L. Fink,
1993).

Pygocentrus
altus: Described from the Upper Amazon by Gill (1870) as a Pygocentrus.
Sometimes considered valid, more usually synonymous with nattereri.
Recently Géry et al. (1987) suggested that this name should be used for the
common Amazonian Pygocentrus and that nattereri should be used
for the southern populations of the genus. Their suggestion is not accepted
here, because samples larger than they examined show the characters used do
not discriminate the populations (William L. Fink, 1993). Gill, T. N. 1870,
On some new species of fishes obtained by Prof. Orton from the Maranon, or
Upper Amazon, and Napo Rivers. Proc. Acad. Nat. Sci. Phila. v. 22: 92-96.
Distribution: Río Marañon or Río Napo, Amazon system, Peru or Ecuador.

The common
name Super Red is meaningless for any specific P. nattereri since these
fish can be highly colored in dark red or reddish-orange within its range. The
common name has been applied to fish from Peru. A look at the geographical forms
of P. nattereriVIEW)
can show that some are more brilliant than others. This color can also be lost
during the fishes growth in your aquarium or a dealer's tank as the fish
matures. The dealer who coined that name for his fish was probably
unaware (at the time) this name could apply to a number of species. It is a
relatively new name in the piranha hobby and it is indeed foolish to just attach
it to just one locality of P. nattereri. As for the reticulated P.
nattereri, this feature is found on some but not all of the fishes from the
middle Amazon. If one wanted to call this a Snakeskin, then that would be fine
for a common name so long as the person understands that feature is
eventually lost behind the brilliant scales. For some unknown reason, this name
was eventually grouped with Super Red. Again its value is a minor concern. The
real value in these wild fishes is the fact they are wild and can replenish a
diminished gene pool if you are into breeding piranhas. Some people collect
solely for their beauty (which is what I do). Others because they are
"wild" and in that there is value.

The
important thing for everyone to remember is be informed
and don't blame dealers if they use a common name. It's up to you the consumer
to know the difference.

*Serrasalmus aff. brandtii and Pygocentrus
nattereri are two species of piranhas, both common in the Viana Lake, which
is formed by the flooding waters of the Pindaré River, a tributary of the left
bank of the Mearim River. A sample composed of 249 specimens of these species
was studied in order to identify diet composition and feeding strategies
employed by the two species. The piranhas were captured tri-monthly, during one
year from March 1999 using gill and fishing nets of different mesh sizes. The
qualitative composition of the diet was analyzed through the frequency of
occurrence method. The feeding strategies employed by the piranhas were inferred
using the graphic method of Costello (1990), modified by Amundsen et al. (1996).
The results indicated that fish was the main food item in the stomach contents
of the two species, followed by plant material, more in the P. nattereri.
Fish and plant material showed different relationships in relation to piranhas
length classes. The graphic analysis of the feeding strategies employed by P
nattereri and *S. aff. brandtii suggest a generalist habit, wide
width niche with strong participation of the within-phenotype component, which
indicated that the majority of individuals of these species use several
resources simultaneously. A multivariate analysis of the ecomorphological index
indicated that the species are discriminated by swimming ability, water column
position and relative prey size. [*This species may well be a
misidentification. Readers are cautioned against assuming this species
identification is correct.]

IN THE
AQUARIUM: Potentially Dangerous To Humans

Probably
the easiest of the genus Pygocentrus to keep as large groups. It is also
the most widespread species found in small groups of 25 up to several hundred
during feeding frenzies. Some hobbyist's mix this species with the 2 members of
genus Pygocentrus (piraya and cariba). While putting them
together is unnatural (not found together in the wild), there is some success in
accomplishing this. However, I prefer to err in caution and suggest only
advanced hobbyist's attempt this under constant supervision. All 3 species of Pygocentrus
are predaceous on each other and your aquarium as a closed system can make
conditions such that might feed on each other. It is my suggestion that a single
P. nattereri may be kept in a 40 U.S. gallon aquarium. Multiple specimens
will require larger aquariums. Tank-raised P. nattereri appear to do
better as small groups than their wild relatives. Though caution is required
when introducing multiple groups because they are cannibalistic. They establish
a pecking order with the larger specimens being more dominant and aggressive.
This is when the opportunity is greatest that smaller specimens might be damaged
or eaten by the larger specimens. Water temperature for in the aquarium can be
between 74-82F. Higher temperature can make the species become more aggressive
and also cause more stress. The species does it plants and I have recorded the
seed eating behavior of the species in the home aquarium.

FEEDING

Foraging
methods vary in different life stages of P.nattereri. During
the day, smaller fish (80-110 mm) search for food. At dawn, late afternoon, and
early evening the larger fish (150-240 mm) search for food. P.nattereri
groups gather in vegetation in order to wait for prey. The group typically
includes around 20-30 fishes. In the daytime P.nattereri can be
seen lurking or ambushing prey. Two other methods for obtaining food employed by
P.nattereri are chasing and scavenging. The hunting mode of
chasing was seen after the fish lie and wait in vegetation. The fish then
proceed to swim after and eat the fish. P.nattereri has a wide
variety of food in its diet, including fins, scales, fish (pieces and whole),
insects, snails, and plants. The plant intake of the animal may be an active way
of gaining food supplies while scanning for prey (Sazima and Machado 1990). Fin
nipping is a common type of feeding among the juvenile and young adult piranhas.
They switch to whole fish when they are larger. The piranha's prey preference
has yet to be determined, but evidence is pointing towards the perciform fishes,
of the family Cichlidae (Kelso-Winemiller et al. 1993). Since fins are
easily accessible and obviously a replenish able resource, fin-nipping is a very
advantageous mechanism of feeding for the piranha.

TEETH

The teeth
of Pygocentrus nattereri are broad, serrated, tricuspid and razor sharp.
These teeth are used for slicing chunks of fish. The teeth are backed up by
strong musculature that have enough force with combination of the razor sharp
teeth to clip off a finger or toe! A medium sized P. nattereri (6 inch
specimen TL) may have teeth as long as 4 mm. For larger specimens, the teeth may
exceed that size in length.

SEXING
AND REPRODUCTION/BREEDING

The
species is not sexually dimorphic. Breeders of piranhas in the home
aquarium note visual differences between the sexes, but this scrutiny is limited
to fish that are observed for a period of time, up to and including pre-spawning
activity. Then some differences can be noted, but subtle due to such activity.
References to body girth or coloration is limited to the female being full of
roe and the male in pre-spawning colors. Other references to thickness of first
ray of anal or body girth is inconsequential to visually attempt to determine
sex when the fish are observed in the wild and in a large group. Therefore it is
of no value in determining sexual morphs of the species. I have placed a few
links to access breeding information being accomplished by hobbyists below. P.
nattereri seems to have a type of courtship display that involves swimming
in circles. This results in ventral-to-ventral interactions among the male and
female. Eggs are placed in the sediment, in bowl shaped nests. These nests are
around 4-5 cm in depth and 15 cm in diameter. The eggs are in clusters and are
attached to the bottom vegetation. There may also be a relationship between the
times of the spawning and the time of the wet season. (Uetanabaro et al. 1993).
The eggs of the piranhas are expelled during spawning and fertilized in the
surrounding water. The adult males and females join in partial fertilization.
The females are most fertile in the months of April and May. Their breeding
habitat tends to be in main bodies of water, such as lagoons (Galvis et al.
1989). A rather large macrophyte population must be present for the young when
they are born, so they can feed.

According
to OPEFE water chemistry (VIEW),
natural water and chemistry would be as follows:

WATER: pH
6.5-7.5 (7.0), 4-14 dH (8). Although in nature, the Paraguay piranhas can
sometimes tolerate water temperatures as low as 59°F (15°C), it should be kept
in water with a temperature from 70-77°F (21-25°C).

The OPEFE
web site and its contents; is disclaimed for purposes of Zoological Nomenclature
in accordance with the International Code of Zoological Nomenclature, Fourth
Edition, Article 8.3 and 8.4. No new names or nomenclature changes are available
from statements at this web site.